1. Technical Field
The present invention relates to a medium feeding device and a recording apparatus including the medium feeding device. The medium feeding device includes a feed roller pair, a transport roller pair, and a medium guiding path section. The feed roller pair includes a feed driving roller driven by power and a feed driven roller to be rotationally driven, and feeds a medium to be fed toward the downstream side in a feed direction. The transport roller pair transports the medium, which is fed by the feed roller pair, toward the downstream side in the feed direction, and includes a transport driving roller that is disposed on the downstream side of the feed roller pair in the feed direction and is driven by power and a transport driven roller that is rotationally driven. The medium guiding path section guides the fed medium up to the transport roller pair.
In the invention, examples of the recording apparatus include an ink jet printer, a wire dot printer, a laser printer, a line printer, a copier, and a facsimile.
2. Related Art
In the past, as disclosed in Japanese Patent No. 3351509, a feeding device provided in a recording apparatus was provided with a pickup roller, a guiding path section, a feed roller pair, and a transport roller pair. The pickup roller of them was provided to pick up a placed paper sheet that served as a medium to be fed, and to feed the paper sheet toward the downstream side in a feed direction. Further, the guiding path section was provided to form a feed path and to guide the paper sheet to be fed.
Furthermore, the feed roller pair included a feed driving roller that was driven by power, and a feed driven roller that was rotationally driven. The feed roller pair was provided to further feed the picked paper sheet toward the downstream side in the feed direction. The transport roller pair included a transport driving roller that was driven by power, and a transport driven roller that was rotationally driven. Further, the transport roller pair was provided to further feed the paper sheet, which was fed by the feed roller pair, toward the downstream side in the feed direction.
FIG. 17 is a side view showing the schematic inner configuration of a recording apparatus in the related art.
As shown in FIG. 17, a feed device 201, which was provided in a recording apparatus 200 in the related art, included a pickup roller 203, a guiding path section 202, a feed roller pair 205, and a transport roller pair 208. The pickup roller 203 was provided to pick up a placed paper sheet and to feed the paper sheet toward the downstream side in the feed direction. Further, the guiding path section 202 was provided to form a feed path and to guide the picked paper sheet up to the transport roller pair 208.
Furthermore, the feed roller pair 205 included a feed driving roller 206 that was driven by power, and a feed driven roller 207 that was rotationally driven. The feed roller pair was provided to further feed the picked paper sheet toward the downstream side in the feed direction. The transport roller pair 208 was formed to transport the paper sheet, which was fed by the feed roller pair 205, to a recording device 209 that was provided further downstream in the feed direction.
First, the picked paper sheet entered a retard roller 204 that requires a predetermined load when being rotated. If paper sheets are doubly fed, so-called retard-separation is performed. Further, only the uppermost paper sheet at the feed driving roller 206 is fed to the transport roller pair 208 by the feed roller pair 205. First, the front end of the paper sheet is nipped by the transport roller pair 208. This is so-called initial biting. Then, the transport roller pair 208 is rotated in a reverse direction, so that the front end of the paper sheet is moved toward the upstream side of a nip point of the transport roller pair 208 in the feed direction. This is a so-called discharge operation.
In this case, the feed roller pair 205 is at a stop. Accordingly, the paper sheet may be deflected between the feed roller pair 205 and the transport roller pair 208 as shown in FIG. 17. The attitude of one end 210 of the paper sheet in a width direction X of the paper sheet is shown by a solid line shown in FIG. 17. Meanwhile, the attitude of the other end 211 of the paper sheet in the width direction X is shown by a chain line. As the attitude of the front end of the paper sheet during the initial biting is significantly inclined with respect to a nip line of the transport roller pair 208, the difference between the attitude of one end 210 of the paper sheet and the attitude of the other end 211 of the paper sheet is increased.
While the attitude of the front end of the paper sheet follows the nip line of the transport roller pair 208, the transport roller pair 208 is rotated in a normal direction so that the front end of the paper sheet is nipped by the transport roller pair 208 again. Accordingly, skew correction was performed in the manner of so-called biting discharge.
After that, the transport roller pair 208 transported the paper sheet to the recording device 209, and recording was performed on the paper sheet by the recording device 209. In this case, the retard roller 204 and the feed driven roller 207 were separated from the feed driving roller 206. Accordingly, it might be possible to reduce so-called back tension that was generated while the paper sheet was transported by the transport roller pair 208.
However, even though the retard roller 204 and the feed driven roller 207 were separated from the feed driving roller 206, it was not enough to remove the difference between the deflection of one end 210 of the paper sheet in the width direction X and the deflection of the other end 211 of the paper sheet in the width direction X. Since the paper sheet was deflected between the feed roller pair 205 and the transport roller pair 208, the paper sheet at the transport roller pair 208 was pushed to the downstream side in the feed direction. Accordingly, there is a concern that the difference is generated between the transport distance of one end 210 of the paper sheet in the width direction X and the transport distance of the other end 211 of the paper sheet in the width direction X due to the difference between the deflections. As a result, there is a concern that skew newly occurs while the paper sheet is transported after the skew correction.
In particular, if the guiding path of the paper sheet between picking-up and the transport roller pair 208 is curved in side view, a trouble is apt to be generated in the case of a paper sheet of which the size is A3 or more.